Device for producing thick and thin effects in a filament yarn

ABSTRACT

An apparatus for producing thick/thin effects in a filament yarn, whereby between inlet and outlet gallets or pairs of pinch rollers, in a stretching zone, the filament yarn contacts the periphery of at least one rotating disk which is heated and is formed with at least one region of reduced radius in which there is no contact between the filament yarn and the disk. The filament yarn is thereby stretched only in regions in which it is heated by contact with the disk periphery and remains thick in those regions in which it is unheated because of the presence of the recess.

REFERENCE TO RELATED APPLICATIONS

This application is a national stage of PCT/DE97/00809 filed 22 Apr.1997 and based, in turn, on German national application 196 26 032.9filed Jun. 28, 1996 under the International Convention.

FIELD OF THE INVENTION

The invention relates to a device for the production of thick/thineffects in a filament yarn, which is stretched in at least onestretching zone limited respectively by an inlet filament-engagingmechanism and an outlet filament-discharge mechanism, whereby betweenthe inlet filament-engaging mechanism and the outlet filament-dischargemechanism a heating device in the form of a heating element (20.1)touched by the filament yarn is arranged. Means are privided for theinterruption of heat supply.

BACKGROUND OF THE INVENTION

According to one embodiment, in the above-mentioned device (see GermanPatent 195 29 315) it has been proposed to use a mechanism for liftingthe filament yarn from a stationary heating device within the stretchingzone, at defined intervals during stretching. The stretching zone islimited by two gallet/transfer roller combinations, between which thementioned mechanism and the stationary heating device are arranged. Thestretching zone can also be limited, at least on one side, by a pair offeeding rollers (with lower/upper rollers).

In the aforementioned construction it can happen that the mechanicalarrangement causes the. The mechanical arrangement in this applicationcan cause the filament yarn to vibrate, which results in uncontrollablemovements of the filament yarn.

OBJECT OF THE INVENTION

It is the object of the present invention to provide an improvedapparatus in which the filament yarn is deflected as little as possibleduring the heat transfer in both treatment stages (heated and notheated).

SUMMARY OF THE INVENTION

This object is attained in accordance with the invention in that theheating surface of the heating element acting on the filament yarn isthe periphery of at least one disk driven about an axis with at leastone region whose radius is reduced with respect to the axis. Accordingto the invention it is proposed to move the heating element and not thefilament yarn. The disk and the yarn path are so arranged with respectto one another that the filament yarn has a tangential contact with thedisk periphery, and this contact does not follow the indentation, i.e.the reduced radius of the disk.

When the filament yarn runs over the circumference of the rotatingheated disk, the yarn length touched by the disk is thereby heated and,is stretched, while the yarn length which does not touch the disk in theindentation of the disk remains cold and therefore is not stretched.

This area remains as the thick effect in the filament yarn.

Due to the fact that the yarn has only tangential contact with the disk,its deflection is minimal between the contact with the periphery and thelack of contact in the region with reduced radius, and thereforeadvantageously no vibration occurs. The ability to reproduce the thinand thick portions and the quality of the effect yarn is improved.

Yarn speed, the rotational speed of the disk and the number of regionswith reduced disk radius determine the number of the thick areas alongthe filament yarn. The length of the recess, i.e. of the area withreduced radius, determines the length of the thick regions in connectionwith the yarn speed and the rotational speed, as well as the thicknessof the disk. Therefore the length of the thick regions can be determinedonly by changing the length of the regions with reduced radius along thedisk periphery, independently of on the number of thick regions alongthe filament yarn.

Advantageously any such disk can be replaced by disks having a differentlength of the region with reduced radius along the disk periphery.

In a further embodiment of the invention two disks can be arranged at adistance from one another and for instance can be driven with rotationalspeeds which do not depend on one another.

Alternately one disk can consist of two or more disk parts which can berotered with respect to one another as to their respective regions withreduced radius.

In one of the embodiments of the invention the axis of rotation of thedisk can be at least approximately parallel to the travel direction ofthe filament yarn. Alternatively the rotation axis of the disk can liein a plane which forms an approximately right angle with the traveldirection of the yarn.

It is common to all embodiments that the disks can be heated by at leastone stationary heating device arranged in immediate proximity thereto,through convection, radiation or induction.

BRIEF DESCRIPTION OF THE DRAWING

The above and other objects, features, and advantages will become morereadily apparent from the following description, reference being made tothe accompanying drawing in which:

FIG. 1 is a schematic side view of a first embodiment of the invention;

FIG. 2 is a plan view of the disk;

FIG. 3 is another embodiment of the invention in a schematic side view;

FIG. 4 is a plan view of a disk consisting of two disk parts.

SPECIFIC DESCRIPTION

In FIG. 1 a device for producing thick/thin effects in a filament yarn 1is shown. Two gallet/transfer roller combinations are used, in the formof an inlet filament-engaging mechanism 6 and an outletfilament-discharge mechanism 6', between which the filament yarn 1 isstretched in a stretching zone I. The stretching zone can be alsolimited at least on one side by a pair of discharge rollers (withupper/lower roller).

In this stretching zone I there is a heating element 20.1, whichconsists of a disk 60 and a stationary heating device 62 arranged inimmediate proximity of the disk. By means of this heating device 62 thedisk can be heated by convection and/or radiation.

The disk 60 is driven by a motor 61 via rotary shaft 65.

From FIG. 2 can be seen that the periphery U of the heated disk 60serves as a heating surface for the filament yarn, whereby the disk 60is shaped with an area with a reduced radius R with respect to therotary axle 65. This area R with reduced radius forms a recess in whichthe filament yarn does not touch the disk periphery so that the yarnremains cold and therefore is not stretched. A thick region thus resultsin the filament yarn. Stretching takes place while the filament yarnruns over the periphery U of the turning heated disk 60 and is heated.

The disk 60 can also have several recesses R and recesses of variouslength in peripheral direction, which can be distributed at random overthe disk periphery. Thereby any desired number, length and distributionof thick regions along the filament yarn can be achieved.

In the embodiment according to FIG. 1 and 2 only one disk 60 is used.Corresponding to the embodiment according to FIG. 3, two disks 60 and60' can be arranged at a distance from each other. It is thus possibledisks 60 and 60' with different rotational speeds, namely by motor 61and 61'.

The two disks 60 and 60' can also be placed on a common shaft withrecesses R turned in different directions. The preferred embodiment isthe one represented in the drawing with separate drives for the disks,because a higher randomization in the distribution of the thick regionscan then be achieved.

It is thus possible to achieve a desired random distribution of thethick regions along the filament due to different and also changingrotational speeds of the two disks 60 and 60'. A heating device 62 islocated here between the disks 60 and 60' and heats both of them. Ofcourse it also possible to provide separate heating devices for eachdisk. Each of the disks 60 and 60' can have an analogous configurationwith the embodiment according to FIG. 2, namely for instance withmutually rotated areas R wherein the filament yarn is not touched.

A further embodiment of the invention is shown in FIG. 4. Here a disk60" is used which consist of two disk parts 60.1 and 60.2 whoserespective areas with reduced radius R₁ and R₂ can be twisted withrespect to each other. Both disk parts 60.1 and 60.2 have a commonrotary shaft 65. Further each is provided with a long hole 67 which istraversed by a clamping screw 68. This way it is possible to turn thetwo disk parts 60.1 and 60.2 with respect to each other and tocorrespondingly change the position of the areas with reduced radius R₁and R₂.

Thereby it is possible to select the length of the produced thickregions, just like in the case of different rotational speeds of thedisks 60, 60'.

In the embodiments according to FIG. 1 to 4 the rotation axis 65 of thedisks 60, respectively 60' and 60" is at least approximately parallel tothe travel direction of the filament yarn. In an embodiment which is notcloser described it is also possible to position the rotation axis ofthe mentioned disk in a plane which forms an approximately right angleyarn.

It is common to all embodiments that the yarn speed, the rotationalspeed and the number of the recessed areas along the disk peripherydetermine the number of thick regions along the filament yarn.Furthermore the length of the recesses along the disk peripherydetermines the length of the thick regions, in combination with the yarnspeed and the rotational speed, as well as the thickness of the disk.Due to fact that the filament yarn 1 touches the periphery of therespective disk only tangentially, its deflection due to contact withthe periphery U, respectively the noncontact with the respectiverecesses, is minimized and does not trigger vibrations.

The rotational speed of disk to or disks can be changed at random, inorder to achieve a random distribution of the thick regions along thefilament yarn. Furthermore it is possible that the disk or the disks beprovided with more than one area with reduced radius; several such areascan have different lengths and/or be distributed randomly in peripheraldirection.

Regarding the design of the heating device it is also possible to heatthe disk itself directly and in this way to eliminate the heating device62.

I claim:
 1. A device for producing thick/thin effects in a filamentyarn, comprising:an inlet filament-engaging mechanism; an outletfilament-engaging mechanism spaced from said inlet filament-engagingmechanism to delimit a stretching zone between said mechanisms, afilament yarn being advanced by said mechanisms through said zone andbeing stretched between said mechanisms; and a heating element acting onsaid filament yarn in said zone and for interrupting heating thereof,said heating element being at least one disk having a periphery engagingthe filament yarn, driven by a rotary shaft and formed with at least oneregion with reduced radius with respect to an axis of rotation of thedisk, and means for heating the at least one disk.
 2. The device definedin claim 1 wherein said heating element includes two disks each having aperiphery contacting said filament yarn and at least one said regionwith reduced radius.
 3. The device defined in claim 2, furthercomprising means for driving said disks independently with differentrotational speeds.
 4. The device defined in claim 1 in which at leastone of said disks comprises two relatively rotatable disk parts twistedwith respect to one another to offset respective regions with reducedradius.
 5. The device defined in claim 1 wherein said means for heatingincludes a stationary convection heater in an immediate proximity ofsaid disk.
 6. The device defined in claim 1 wherein said means forheating includes a stationary radiant heater in an immediate proximityof said disk.
 7. The device defined in claim 1 wherein said means forheating includes a stationary induction heater in an immediate proximityof said disk.
 8. The device defined in claim 1, further comprising meansconnected with said disk for changing a rotational speed thereof.
 9. Thedevice defined in claim 1 wherein said disk is provided with a pluralityof regions of reduced radius around a periphery of said disk.
 10. Thedevice defined in claim 9 wherein said regions are of differentcircumferential length.
 11. The device defined in claim 1 wherein amultiplicity of regions of reduced radius are randomly distributedaround a periphery of said disk.
 12. The device defined in claim 1wherein a plurality of said disks are provided and a multiplicity ofsaid regions of reduced radius are randomly distributed aroundperipheries of said disks.